There are a number of considerations relevant in the art of protective and decorative coating systems for substrates, such as wood substrates, including cabinets, floors, furniture, and the like. As will be appreciated, such coating systems are often made up of more than one coating layer. Porous substrates, such as wood, for example, are often coated with multi-layer composite coating systems that include a toner layer, a stain layer, a sealer layer, and a topcoat layer. Typically, the toner and/or stain layer(s) are coloring layers, i.e., they provide coloring. The sealer layer is often a protective layer that is sanded to provide a smooth finish, while the topcoat layer is often a protective layer that provides surface properties, such as mar and scratch resistance.
In many cases, the various coating layers in such multi-layer composite coating systems, including the coloring layers, such as stains, are deposited from coating compositions that contain radiation curable materials, such as resins that are curable by exposure to ultraviolet (“UV”) radiation. Such resins can provide coatings exhibiting excellent properties, such as adhesion properties, and are often desirable for wood finish applications because of the heat sensitivity of wood, which often makes certain thermosetting coatings unfavorable.
There are some drawbacks, however, to using radiation curable materials in such coating compositions. Capital investment may be required to provide equipment, such as UV lamps, that are necessary to cure coating compositions that contain radiation curable resins. Moreover, in some cases, such as when it is desired to utilize wiping stains, toxicity issues may prevent the use of certain radiation curable materials.
As a result, it is desired to provide coating compositions, such as stain and toner compositions, that are free of radiation curable materials, but which can be used to provide multi-layer composite coating systems exhibiting acceptable properties, including acceptable adhesion properties.